1. Field of the Invention
In the present state of the art, no device is available which permits to control automatically the quantity of the metallic middlings and the density of the abrasive mixture which is collected at the discharge end and which is re-introduced in the apparatus for the sawing of granite and hard stones. Any control, therefore, at present is carried out manually by the operator with no regularity nor uniformity. Further, the eventual modifications of the properties of the abrasive mixture are performed by varying the periods of time of intervention of the washer-recuperator in order to regulate the density and by placing in operation the ratchet gear which controls the dosing device of the middlings which varies the quantity of the abrasive middlings being added to the mixture.
The density of the mixture is defined by weighing a quantity of the abrasive mixture manually removed from the well reservoir of the pumping station, or may be determined by an experienced operator according to the feel of the mixture.